Modular systems have developed over the decades from a first generation centered upon a processor bus and primarily used for control applications to a second generation centered upon a chip interconnect for usage in communications and control. First generation technology originated about 1980 and utilizes VERSAmodule Eurocard (VMEbus) technology along with Multibus I and II standards. Second generation products became available around 1994 and utilizes CompactPCI (Peripheral Component Interconnect) buses. Various technologies and standards have been developed in the second generation including Ethernet, Packet, Backplane extension, and others, extending to integration of telephony with computing, how swap, high availability, wide operating system support, wide PCI silicon support, and the like. Various standards have been created to facilitate connectivity and cooperation among components and systems. One such standard is the Peripheral Component Interconnect (PCI) Industrial Computer Manufacturers Group (PICMG™) 2.16 specification.
Technology is currently at the beginning of a new, third generation that extends capabilities to fabric interconnects, primary applications, central office telecommunications, communications control, and data communication dense servers. Features implemented and planned for the third generation include carrier grade features, performance expansion to tens of gigabits out to terabits, backplane scalability to support fabrics, and processing scalability to include multiple processors, and digital signals processors. Third generation supplies support for convergence of access, core, optical, switching, server, storage, voice, data, video, and wireless functions.
Standardization bodies taking part in the development of third generation standards have considered the desirability of maintaining form factors and interconnect configurations of previous generation systems, but chose for various reasons to establish completely new standards. The standardization bodies determined that board areas from former generations are too small and board spacing too narrow to accommodate emerging applications. Previous generation heat dissipation was found inadequate for next generation semiconductors and backplane capacity severely limited. Signal integrity and electromagnetic compatibility have arisen as new problems. Old generation mechanical standards fail to support input/output requirements.
As a result, third generation standards specify form factors and configurations that are incompatible with the standards of previous generations. A consequence of the new standards is that a large body of highly useful technology and many products are rendered obsolete.